Setback switch



Feb 21, 195

J. D. JORDAN ETAL SETBACK SWITCH Filed May 5, 1943 FIG.4

l6 INVENTORS .m 0. JOAN Patentecl Feb. 21, 1959 PAEEN i" EFEQE G. Ferris, Harvard, 113., assignors to the United States of America as represented by the Scoretary of the Navy Application May 5, 1943, Serial No. 485,782

(Cl. Edd-52) 7 Claims.

This invention relates to an improved set-back switch which is adapted to be mounted within an explosive projectile to close at least a portion of an electrical detonating circuit after the projectile has been fired.

The set-back switches of the prior art are dependent upon operation by movement of numerous mechanical parts. Many of these mechanical parts are close-fitting and require precision machining. Also, it is often difficult to assemble the parts, and if any one part is improperly made or assembled, the operation of the entire switch fails. Therefore, the objects of this invention are to provide a set-back switch which will operate to close at least a portion of an electrical dctonating circuit within an explosive projectile upon the acceleration of the projectile when fired; to provide a set-back switch which will not operate to close the circuit until the projectile is fired; to provide a switch which is positive in function; and to provide a set-back switch wherein the numerous precision-made mechanical parts are eliminated. Still further objects of the invention, not specifically mentioned above, will be apparent during the course of the following description.

In the drawings:

Fig. l is a diagrammatic view showing the invention mounted within a projectile;

Fig. 2 is a vertical sectional view of the invention;

Fig. 3 is a fractional vertical sectional view of the invention showing the parts in position at th start of the acceleration of the projectile;

Fig. 4 is a fractional vertical sectional view showing the parts in the position after the acceleration of the projectile;

Fig. 5 is a cross-sectional view taken on line 5-5 of Fig. 2; and,

Fig. 6 is an inverted perspective view of a portion of the invention.

In the drawings, similar reference numerals will be used to indicate like parts throughout the views.

A body member 5%, preferably in the form of a cylindrical block of Lucite or other suitable insulating material, is positioned within the projectile as shown in the Fig. 1. An electrical detonating circuit 0, having a proximity fuze and suitable source of current B interposed therein, is also mounted within the projectile. The terminal ends of the circuit C are positioned within the block it as will hereinafter be described.

Suitably positioned within the block it is a bore or cylinder H. Wires l2 and 53, which form a portion of the detonating circuit C, are stripped of insulation at their terminal ends to form contact members it and I5. These contact members it and 55 are mounted in the insulating block iii through suitable bores therein and are located on either side of, and at right angles to, the bore H and are positioned so that at least a portion of each member extends within the bore (see Fig. 5). It will be noted that contact members 54 and l 5 form a restriction within bore H and provide a support for a flexible insulating disc it which is also positioned within the bore H. A pellet of malleable metal ll, which may be Woods metal, is also positioned within the bore ll beyond contact members M and I5 and is supported by the flexible insulating discs IS. A suitable abutment i8 is provided to act as a stop for the malleable metal i! when set-back force is exerted thereon, the abutment is being located outside of the body member it] in the form of the invention shown. However, it will be obvious that this abutment 58 may take the form of a disc or the like positioned within the rear portion of the bore H beh nd the contact members I l and it.

The operation of the device will be readily understood from the foregoing description. Before the projectile is fired, the switch is in the position shown in Fig. 2 wherein the circuit C is in opened position because of the space between contact members I4 and I5 of wires l2 and i3 respectively. After th projectile has been fired, the force of the set-back acting upon the malleable metal l'l forces the metal ll rearwardly against the flexible insulating disc 16 causing the insulating disc is to bend and assume the position as shown in Fig. 3. Continued set-back force upon the malleable metal will force the insulating disc through the restriction form by contact members It and it against the abutment l8. Simultaneously, the malleable metal ii is also forced through the restriction and contacts members M and it, thus closing at least a portion of the circuit C.

It will be obvious from the foregoing that the set-back switch which forms the subject matter of this invention is extremely simple in operation, positive in function, and the numerous mechanical parts formerly utilized to make a device of this character have been eliminated.

We claim:

1. A set-back switch adapted to be mounted within a projectile to close at least a portion of an electrical detonating circuit upon the application of set-back force created when the projectile is fired comprising a body member, a bore in said body member, contact members mounted in spaced relation from each other in said body member, at least a portion of said contact members extending into said bore, and malleable metal positioned in said bore capable of being moved upon the application of set-back force, said malleable metal making contact between said contact members when moved upon the application of set-back force.

2. A set-back switch adapted to be mounted within a projectile to close at least a portion of an electrical detonating circuit upon the application of set-back force created when the projectile is fired comprising a body member, a bore in said body member, contact members mounted in spaced relation from each other in said body member, at least a portion of said contact members extending into said bore, malleable metal positioned in said bore capable of being moved upon the application of set-back force, said malleable metal making contact between said contact members when moved upon the application of set-back force, and means for preventing said malleable metal from making contact between said contact members until set-back force is exerted upon said malleable metal.

3. A. set-back switch adapted to be mounted within a projectile to close at least a portion of an electrical detonating circuit upon the application of set-back force created when the projectile is fired comprising a body member, a bore in said body member, contact members mounted in spaced relation from each other in said body member, at least a portion of said contact members extending into said bore, malleable metal positioned in said bore capable of being moved upon the application of set-back force, said malleable metal making contact between said contact members when moved upon the application of set-back force, and displaceable insulating means positioned in said bore between said contact members and said malleable metal for preventing said malleable metal from making con tact between said contact members, said insulating means being displaceable upon the application of set-back force. 4. A set-back switch adapted to be mounted within a projectile to close at least a portion of an electrical detonating circuit upon the application of set-back force created when the projectile is fired comprising a body member, a bore in said body member, contact members mounted in spaced relation from each other in said body member, at least a portion of said contact members extending into said bore forming a restriction therein, malleable metal positioned in said bore beyond said restriction capable of being moved within the restriction and making contact between said contact members upon the application of set-back force.

5. A set-back switch adapted to be mounted within a projectile to close at least a portion of an electrical detonating circuit upon the application of set-back force created when the projectile is fired comprising abody member, a bore in said body member, contact members mounted in spaced relation from each other in said body member, at least a portion of said contact members extending into said bore forming a restriction therein, malleable metal positioned in said bore beyond said restriction capable of being moved within the restriction and making contact between said contact members upon the application of set-back force, and the means of preventing said malleable metal from entering the restriction until set-back force is exerted upon said malleable metal.

6. A set-back switch adapted to be mounted within a projectile to close at least a portion of an electrical detonating circuit upon the application of set-back force created when the projectile is fired comprising a body member, a bore in said body member, contact members mounted in spaced relation from each other in said body member, at least a portion of said contact members extending into said bore forming a restriction therein, malleable metal positioned in said bore beyond the restriction capable of being moved within the restriction and making contact between said contact members upon the application of set-back force, and a displaceable insulating disc positioned within said bore upon the restriction formed by the contact members to separate said members from said malleable metal, said insulating disc being displaceable upon the application of set-back force.

7. A set-back switch adapted to be mounted within a projectile to close at least a portion of an electrical detonating circuit upon the application of set-back force created when the projectile is fired comprising a body member of insulating material, a bore in said body member, a pair of contact members mounted in said body member at right angles to said bore and positioned within said body member so that a portion only of each contact member extends into said bore, said contact members being exposed ends of wires which form a part of the electrical detonating circuit, a flexible insulating disc positioned within said bore and mounted upon the portion of the exposed ends of wires which form the contact members, and malleable metal positioned in said bore beyond said insulating disc capable of being moved upon the application of set-back force, the set-back force exerted upon said malleable metal being sufficient to bend said insulat ing disc and force the same beyond the'exposed ends of wire which form the contact members, thereby enabling the malleable metal to contact the contact members.

JAMES D. JORDAN. ROBERT G. FERRIS.

REFERENCES CITED The following references are of record in the file or" this patent:

FOREIGN PATENTS Number Country Date 602,624 France Aug. 25, 1925 708,105 France Mar. 29, 1930 728,341 France Dec. 16, 1931 798,648 France Dec. 3, 1935 

